/*
 *
 *  *  Copyright 2010-2016 OrientDB LTD (http://orientdb.com)
 *  *
 *  *  Licensed under the Apache License, Version 2.0 (the "License");
 *  *  you may not use this file except in compliance with the License.
 *  *  You may obtain a copy of the License at
 *  *
 *  *       http://www.apache.org/licenses/LICENSE-2.0
 *  *
 *  *  Unless required by applicable law or agreed to in writing, software
 *  *  distributed under the License is distributed on an "AS IS" BASIS,
 *  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  *  See the License for the specific language governing permissions and
 *  *  limitations under the License.
 *  *
 *  * For more information: http://orientdb.com
 *
 */
package com.orientechnologies.orient.core.tx;

import com.orientechnologies.common.comparator.ODefaultComparator;
import com.orientechnologies.orient.core.db.ODatabaseDocumentInternal;
import com.orientechnologies.orient.core.index.OIndex;
import com.orientechnologies.orient.core.index.OIndexInternal;
import com.orientechnologies.orient.core.storage.OStorageTransactionIndexChanges;
import com.orientechnologies.orient.core.storage.OStorageTransactionIndexKeyChanges;
import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;

/**
 * Collects the changes to an index for a certain key
 *
 * @author Luca Garulli (l.garulli--(at)--orientdb.com)
 */
public class OTransactionIndexChanges implements OStorageTransactionIndexChanges {

  public enum OPERATION {
    PUT,
    REMOVE,
    CLEAR
  }

  public NavigableMap<Object, OTransactionIndexChangesPerKey> changesPerKey =
      new TreeMap<Object, OTransactionIndexChangesPerKey>(ODefaultComparator.INSTANCE);

  public OTransactionIndexChangesPerKey nullKeyChanges = new OTransactionIndexChangesPerKey(null);

  public boolean cleared = false;

  private OIndexInternal resolvedIndex = null;

  public OTransactionIndexChangesPerKey getChangesPerKey(final Object key) {
    if (key == null) return nullKeyChanges;

    return changesPerKey.computeIfAbsent(key, OTransactionIndexChangesPerKey::new);
  }

  public void setCleared() {
    changesPerKey.clear();
    nullKeyChanges.clear();

    cleared = true;
  }

  public Object getFirstKey() {
    return changesPerKey.firstKey();
  }

  public Object getLastKey() {
    return changesPerKey.lastKey();
  }

  public Object getLowerKey(Object key) {
    return changesPerKey.lowerKey(key);
  }

  public Object getHigherKey(Object key) {
    return changesPerKey.higherKey(key);
  }

  public Object getCeilingKey(Object key) {
    return changesPerKey.ceilingKey(key);
  }

  public Object[] firstAndLastKeys(
      Object from, boolean fromInclusive, Object to, boolean toInclusive) {
    final NavigableMap<Object, OTransactionIndexChangesPerKey> interval;
    if (from != null && to != null) {
      interval = changesPerKey.subMap(from, fromInclusive, to, toInclusive);
    } else if (from != null) {
      interval = changesPerKey.headMap(from, fromInclusive);
    } else if (to != null) {
      interval = changesPerKey.tailMap(to, toInclusive);
    } else {
      interval = changesPerKey;
    }

    if (interval.isEmpty()) {
      return new Object[0];
    } else {
      return new Object[] {interval.firstKey(), interval.lastKey()};
    }
  }

  public Object getFloorKey(Object key) {
    return changesPerKey.floorKey(key);
  }

  public OIndexInternal resolveAssociatedIndex(String indexName, ODatabaseDocumentInternal db) {
    if (resolvedIndex == null) {
      final OIndex index = db.getMetadata().getIndexManagerInternal().getIndex(db, indexName);
      if (index != null) resolvedIndex = index.getInternal();
    }

    return resolvedIndex;
  }

  public OIndexInternal getAssociatedIndex() {
    return resolvedIndex;
  }

  @Override
  public boolean isClearIndex() {
    return cleared;
  }

  @Override
  public OStorageTransactionIndexKeyChanges getNullChanges() {
    nullKeyChanges.setIndex(getAssociatedIndex());
    return nullKeyChanges;
  }

  @Override
  public SortedMap<Object, OStorageTransactionIndexKeyChanges> getChanges() {
    TreeMap<Object, OStorageTransactionIndexKeyChanges> map =
        new TreeMap<>(ODefaultComparator.INSTANCE);
    for (Map.Entry<Object, OTransactionIndexChangesPerKey> keyChanges : changesPerKey.entrySet()) {
      OTransactionIndexChangesPerKey changes = keyChanges.getValue();
      changes.setIndex(getAssociatedIndex());
      map.put(keyChanges.getKey(), changes);
    }
    return map;
  }
}
